A team of American researchers has developed a new imaging tool that can take pictures of cells and molecules deep inside the body. Sanjiv Sam Gambhir, professor of radiology and biochemistry at Stanford University Medical School heads a new study that validates use of Raman spectroscopy in animals.

The laser-based imaging tool is the first to use light rather than radiation to gather molecular signals. Gambhir explains that researchers injected mice with nanoparticles directed to find cancer cells. "The nanoparticles make the light pop off [of] them. The light pops back out of the body and then they are detected."

This scattering of light ? called a spectral fingerprint ? is unique to each type of molecule and can be measured. Gambhir says the signals are stronger and longer-lived than other imaging methods and can transmit information about multiple targets simultaneously. "One signal might reflect a target on a cancer cell. Another signal might reflect a protein that a cancer cell secretes. Another signal might reflect a protein inside the cancer cell."

Gambhir says Raman spectroscopy has great promise for detection of breast and other cancers at a very early stage. "When a male or female feels a one centimeter lump in their breast that one centimeter lump is about three billion cells. So, how do we see fewer cells? How do we see 300 cells?"

Gambhir says Raman spectroscopy may provide some answers by going inside the body and looking for the bad protein present on cancer cells. "If this technique is very sensitive and can detect very low level of signal, then it can detect fewer and fewer cells."

Gambhir believes that if his research can achieve positive results in human trials, Raman spectroscopy could become a routine medical procedure within three years. Gambhir's research appears in the Proceedings of the National Academy of Sciences